/*
 * Copyright (c) 2005, 2006, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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 */

package javax.annotation.processing;

import javax.lang.model.element.AnnotationMirror;
import javax.lang.model.element.AnnotationValue;
import javax.lang.model.element.Element;
import javax.tools.Diagnostic;

/**
 * A {@code Messager} provides the way for an annotation processor to report
 * error messages, warnings, and other notices. Elements, annotations, and
 * annotation values can be passed to provide a location hint for the message.
 * However, such location hints may be unavailable or only approximate.
 * 
 * <p>
 * Printing a message with an {@linkplain javax.tools.Diagnostic.Kind#ERROR
 * error kind} will {@linkplain RoundEnvironment#errorRaised raise an error}.
 * 
 * <p>
 * Note that the messages &quot;printed&quot; by methods in this interface may
 * or may not appear as textual output to a location like {@link System#out} or
 * {@link System#err}. Implementations may choose to present this information in
 * a different fashion, such as messages in a window.
 * 
 * @author Joseph D. Darcy
 * @author Scott Seligman
 * @author Peter von der Ah&eacute;
 * @see ProcessingEnvironment#getLocale
 * @since 1.6
 */
public interface Messager {
	/**
	 * Prints a message of the specified kind.
	 * 
	 * @param kind
	 *            the kind of message
	 * @param msg
	 *            the message, or an empty string if none
	 */
	void printMessage(Diagnostic.Kind kind, CharSequence msg);

	/**
	 * Prints a message of the specified kind at the location of the element.
	 * 
	 * @param kind
	 *            the kind of message
	 * @param msg
	 *            the message, or an empty string if none
	 * @param e
	 *            the element to use as a position hint
	 */
	void printMessage(Diagnostic.Kind kind, CharSequence msg, Element e);

	/**
	 * Prints a message of the specified kind at the location of the annotation
	 * mirror of the annotated element.
	 * 
	 * @param kind
	 *            the kind of message
	 * @param msg
	 *            the message, or an empty string if none
	 * @param e
	 *            the annotated element
	 * @param a
	 *            the annotation to use as a position hint
	 */
	void printMessage(Diagnostic.Kind kind, CharSequence msg, Element e,
			AnnotationMirror a);

	/**
	 * Prints a message of the specified kind at the location of the annotation
	 * value inside the annotation mirror of the annotated element.
	 * 
	 * @param kind
	 *            the kind of message
	 * @param msg
	 *            the message, or an empty string if none
	 * @param e
	 *            the annotated element
	 * @param a
	 *            the annotation containing the annotation value
	 * @param v
	 *            the annotation value to use as a position hint
	 */
	void printMessage(Diagnostic.Kind kind, CharSequence msg, Element e,
			AnnotationMirror a, AnnotationValue v);
}
